The relationship between genotype and environmental temperatures will be investigates in four related taxa of blister beetles, where the me the pattern of metamorphosis as well as the rate of development appears to be influenced by temperature. Norms of reaction (genotype-environment interaction) will be established for these taxa collected as adults from five distinct geographical areas (Florida, Illinois, Mississippi, Tennessee, and Texas) by analyzing the development of larval siblings at natural soil temperature cycles characteristic of each area. In addition, each taxon will be reared at constant temperatures. Earlier studies are of limited value because they did not match sibling sets, the direct comparison of different populations, or the natural temperature cycles that will be utilized here. Virgin adults from laboratory rearings will be mated to investigate inheritance of developmental patterns.